Inner tube for pneumatic tires.



H. C. BOGGS.

INNER TUBE FOR PNEUMATIC TIRES. A PPLICATION FILED IuLY 3, 1916.

1,227,108. Patented May 22,1917;

Boees, `a citizen HAMILTON CLAYTON-BOGGS, 0F DECATUB, ALABAMA.

INNER TUBE 'FOB'v PNEUMATIC TIRES.

specification of Letters raient.

Application filed July 3, 1916. Serial N o. 107,423.

To all whom t may concern Be it known that I, HAMILTON CLAYTON of the United States, vresiding at Decatur, in the county of Morgan and State of Alabama, have invented certain new and useful Improvements in Inner Tubes for Pneumatic Tires; and I do hereby declare the following to be a full, clear,

and exact description of the invention, such as will enable others skilled in the art to which it appertains tomake and use the same.

My present invention relates to that general class of pneumatic tiresknown as selfhealing tires, and to that particular type of said class in which a comparatively thick inner tube composed mainly of elastic rubber is used, and in which the material of the inner tube is held under, compression instead of under tension' when the said inner tube is mounted in the shoe or casing and inflated.

My present invention is intended more especia ly to provide certain improvements over the construction shown in my Patent No. 1,182,871, grantedMay 9, 1916, and entitled Improvements ininflatable tires.

In the structure shown lin that patent,

when a perforation .of any appreciable size' is made in the shoe, the soft rubber of the inner tube vwill be forced by the` pressure of the air within the same to lproject into the crack or opening and such projecting portion will be pinched off, the result being that in a short'time va perforation will be madein the inner tube itself, and the sam will become deflated. v According to my present invention, I provide a reinforce consisting of canvas embedded in the rubber ofthe inner tube, preferably near the exterior. This canvas may consist of a single layer or plurality of' layers, and may be continued entirely around the inner tube, or so placed as to protect the portion only thereof that is liable to be forced up into the cracksor perforations in the shoe. i

According to my invention, I provide an inner tube, which, when deflated, has vwalls of suiicient thickness to assume a ielding but relatively fixed cross section, t at will enable the tube toV be inserted in or removed from the shoe without any danger of creasing or pinching, and yet, when the pneumatic pressure is applied, the tube will adapt itself to the inner contour of the shoe, compressing the rubber in the tube, and `bearing firmly against the inner walls of the shoe. The thickness and body of the materiali in the tube will also tend to stillen the casing, preventing thel latter from folding or bending at sharp angles when in service.` But when the inner tube becomes deflated from any cause, as from a leaky valve or the like, will fold upon itself in such a way as to interpose an. elastic rubber cushion between the tread portion of the shoe and the rim of the wheel, thereby in .a large measure preventing the cutting by the rim of either Ythe shoe or the tube.

The exterioriof the .tube is initially made of Asomewhat greater circumference in cross section than the interior of the casing, so that when assembled the shoe will compress the rubber in the tube.

My invention will be understood by reference to the accompanying drawings, in which, Figure 1 shows a crosssection through the shoe .and the inner tube, the inner tube being deflated, but no external pressure being applied to the shoe.

Fig. 2 shows a similar section to Fig. 1,-

' Patented May 22, 191'?. i

except that the inner tube has been iniatd.

Fig. 8 shows the inner tube in the deflated condition, and pressure applied to the tread of the shoe, and illustrates the efiiciency of the Adevice against the cutting 'of -the sh'oe by the rim; and

Fig. 4' shows a modification in which there are applurallty of plies of canvas throughout the ma]or portion of the inner tube, and a single ply in that portion thereof next to' the rim of the wheel.

A represents the shoe of the tire, which may be constructed in, any usual or conrenient way. In the various drawings, I :have shown a tire of the clencher type, vmount'edin a well-known form of clencher rim C. 'l The inner tubeB 'is made of molded rubber, preferably thicker in the ortion b,

adapted to engage in the tread o lthe shoe,

and thinner in the portion b', adapted to rubber exterior to the canvas will prevent project into those portions of the shoe which are protected against puncture by the run C.

Embedded in this inner tube, preferably near its outer surface, I provide one. or more strips of canvas D, which may extend entirely around the inner tube or may terminate at the points marked d, in Figs. 1 and 2, beyond which points, the inner tube and shoe are protected against puncture by the rim.

In Figs. 1 and 2, I have shown a single strip of canvas embedded in the outer portion of the inner tube, while in Fig. 4, I have shown double strips of canvas D, extending throughout those -portions of the inner tube, that are most liable to be punctured, and terminating at the points d from which points a single strip of canvas d2 is carried around that portion of the tube nexta to the rim.

When deflated andin the normal position, in a substanthe inner tube is constructed tially heart-shaped cross section, shown in Fig. 1', vinwhich the .tip of theheart which projects `in toward the rim is flattened somewhat as atl, and bears the tapered sides 2 and 3 engage corresponding portions of the shoe or casing. The sides of the inner tube are provided with annular grooves 4 and 5, and the periphery of the inner tube is provided with an annular groove 6, between which grooves l and 6 and 5 and 6, there are U-shaped loops having bearing'surfaces which engage the interioroftheshoeat equi-distant spaces from the center ofthe 'tread ofthe shoe.

. Thus, we havefthree annular depressions 1n the outer walls of the inner tube, which leave spaces lenticular in cross section between the outer walls of the tube and the inner walls of the shoe. When the inner tube is inflated its thick walls Vare forced outward under pressure into these lenticular spaces until they tsnugly .against the inner walls of the shoe, the result being that 4the whole inner layers of the inner tube are placed under a state of compression, and if the u iner .tube is punctured as by a nail or thelike, the wound is automatically closed `byfthe compression of the rubber.

e canvas near the outer walls of the inner tube will give sullicient stiffness to the rubber to prevent it being forced into any puncture in the shoe, and thus the life of the inner tube there is little danger of deflation of the said tube 'except from leaky valves or other abnormal conditions.

By having the canvas reinforce near the outer wall of the inner tube, an' armor therefor is provided without materially impairing the compression feature of the thick wall of the tube, while-,the thin layer of 4the inner tube as abrasion.

against the rim, and v tube is deated, annular is greatly prolonged, and

with one or more .1

excessive rubbing of the canvas on the inner wall of the shoe.

Since the most of likely to occur at or near the tread lof the shoe, I preferably thicken these portions of at b and thereby give a better self-healing of compressed rubber atl that'point.

en from a leaky valve or any other reason, the inner tube does become deliated, the lower portion of the tire, or that portion pressing on the ground, will assume the position shown in Fig. 3, in which the thick walls of the inner tube are folded upon themselves, as shown and forming a resilient cushion, thus in a large measure protecting bot-h from being cut or materially injured by the rim. When the tire is condition, the layer or layers located near the exterior of will serve to protect the inner rubber portions of the inner tube from rupture or of canvas being While I have shown the tire as applied to a clencherrim, and shoe, it will be -obviously applicable to any other well-known form of rim and shoe.

Having thus described my invention, what I claim and desire to secure by Letters ,Patent of the Unite States, is:

1. Ina tire, the combination with. a rim ,andl a shoe connected thereto, of'a continuous annular inner tube mounted in said shoe, 'said tube being made of soft rubber with comparatively thickwalls, andi reinforced with one or more layersof canvas embedded therein, l said .tube being substantially heart-shaped in crossfsection when deflated, and thewalls 4 of said tube being; ofgreater thickness' at thel outer peripher than at the inner. periphery, said tube ingprovided withannular grooves in f its sides ripher formingwith` the shoe when' the spaces, lenticular in cross section, iniated the walls ofthe tube are forced outward compressing the innerlayersv of rubber thereof, and filling up said lenticu lar spaces, and whereby, when the tire is collapsed, a yieldin `cushion is providedv between the tread o the tire and the rim, substantially as described'. v l

2. In a pneumatic tire, the combination with a casing of an inner-tube therefor comthe shoe and the inner tubel the inner tube4 and outerA pe-v the perforations are 7o.

effect to the inner layers in this collapsed whereby when thetube is posed of a thick annular shell of soft 'rub-lv ber, made thicker on ,itsl outer than on its inner periphery and molded to a set form ayers of canvas inserted in lthe body and near the `outer periphery thereof, said tube being provided with a wide depression in the outer periphery thereof,

and with oppositely disposed similar depressions in the sides thereof, said depressions being separatedv by uninterrupted curved annular outwardly-projecting looped portions, adapted to engage and to have rolling contact with the interior of said casing,

when deflated, the Whole inner tube being adapted, when inflated, to forni a continuous, thick, elastic lining, held under compression by, and with its tread and side porl In testimony whereof, I aiiX my signature.

HAMILTON CLAYTON BOGGS. 

